The present invention relates to a reflective type liquid crystal display device and a method of manufacturing the same, and more particularly, to an improvement on a reflective part of a reflective type liquid crystal display device.
Recent years have seen a rapid progress of display devices. Of the display devices hitherto known, a liquid crystal display device is advantageous in several respects. First, it consumes a little electric power. Second, it is thin. Third, it has a long life. Very recently, television sets have been made using liquid crystal displays.
Most liquid crystal television sets use a so-called Guest-Host type liquid crystal, a mixture of nematic liquid crystal and dichroic dye. This is because the Guest-Host type liquid crystal consumes little electric power and has a large field angle. If a reflective type display device using Guest-Host type liquid crystal is to present a picture with high contrast, it must have a reflective film with a white scattered surface. Hitherto, such a reflective film has been white metal film with small depressions, e.g. an aluminum film with small depressions. A few methods of forming such a white metal film are disclosed in Japanese Patent Disclosure No. 55-9517. They are:
(1) To sputter and deposit metal in an atmosphere under regulated conditions, e.g., temperature. PA1 (2) To etch a white metal film, thus roughening the surface of the film. PA1 (3) To roughen the surface of a white metal film by shot blasting
These methods are disadvantageous. In any of these methods, small protrusions or depressions are formed directly on the surface of the reflective film. The edges of the protrusions or depressions thus formed inevitably have an acute angle. Light applied on the edge of each protrusion or depression will undergo multiple reflection and a portion of the light will be absorbed into the reflective film. Consequently, the reflective film will present a dark image.